The present invention relates to an improvement in a hose clamping device for fixing an elastic hose on, for example, an end of a fluid pipe.
Hose clamping devices are widely used for the purpose of clamping and fixing elastic hoses to ends of fluid pipes of various equipment. A typical conventional hose clamping device has a clamp band which is adapted to be placed around the hose in a ring-like configuration such that the opposite ends of the band overlap each other. A holder is provided on one end of the band which is adapted to underlie the other end when wound in the ring-like configuration. A fixing screw rotatably carried by the holder is adapted to engage a plurality of slots formed in the end portion of the band which overlies the other end portion. The slots are spaced at the same pitch as the screw of the fixing screw. As the fixing screw is tightened, the length of the overlap of the ends of the band is increased, thereby tightening the hose onto the pipe end. As a means of a reference for this tightening, a stopper is provided so as to be contacted by the end extremity of the overlying end of the band.
An example of a known hose clamping device having such a stopper is shown in FIGS. 3 and 4. As will be seen from these Figures, the end extremity 1A of the overlying end is adapted to move forwardly along the upper surface of the ring-like band 1 as the fixing screw is tightened. A stopper 2 is formed on the band at a position ahead of the end extremity 1A. The stopper 2 is defined by a tab which is punched from the band 1. The tab constituting the stopper 2 is bent above the surface over which the end extremity 1A moves so that the underside thereof faces the end extremity 1A when tightened. In such prior art clamping devices, cutout 2A formed by punching is positioned between the stopper 2 and the end extremity 1A. In operation, therefore, the end extremity 1A moves along the periphery of the underlying portion of the band so as to first cover the cutout 2A and then abut the stopper 2.
Known hose clamping devices of this type, however, are deficient in that the clamp tends to become unstable when the fixing screw is excessively tightened. Because the tab constituting the stopper 2 is raised by being pulled in the direction of movement of the end extremity 1A, the stopper is forced further up and away from the cutout 2A when pressed strongly by the end extremity 1A as a result of excessive tightening of the fixing screw. As will be seen from FIGS. 4 and 5, an offset exists between the base end of the tab constituting the stopper 2, i.e., the uncut edge of the cutout 2A and the portion of the stopper 2 contacted by the end extremity 1A. As a result, the end extremity 1A of the band abutting the stopper 2 produces a force which tends to further raise the stopper 2 by bending the same about the above-mentioned base end. Consequently, a gap S is formed between the portion of the hose clamp around the base of the stopper 2 and the hose 3 which is hatched in FIG. 6. This gap results non-uniform unstable in clamping of the hose to the fluid pipe.